This invention relates to a disc recording and reproducing device capable of minimizing a trouble occurring in writing in a TOC (table-of-contents) area due to stoppage of supply of an electric power or other cause during continuous recording of information.
Since a Compact Disc (CD) was developed as a superior recording medium to an analog record, some other new recording media have been developed. A Mini Disc (MD) is one of these newly developed recording media. The Mini Disc is attracting attention of the industry as a prospective audio recording medium which has portability of the Compact Cassette and also operability and tone quality of the Compact Disc.
Since the MD has adopted a new audio compression system while employing the PCM system similar to the CD, the MD can realize a high tone quality which is about the same as the CD with the amount of information which is about one fifth of the CD. For this reason, reproduction time which is about the same as the CD can be realized with a disc having a diameter which is about half that of the CD.
There are two types of MD. A reproduction only MD is made of an optical disc similar to the CD. In the case of an MD which is capable of both recording and reproduction MD is made of a magneto-optical disc. An MD player adapted to these two types of MDs has not only an optical head for recording and reproduction but also a magnetic head for writing.
In a digital disc such as the CD, a TOC (table-of-contents) area is generally provided before a recording area so as to enable a prompt search of a head of a music piece during playback or a prompt search of an empty area for additional recording. A start time (start address) of each music piece and an end time of the disc, etc. are recorded in the TOC area in the form of a table.
For recording plural music pieces continuously in a disc having the TOC area, the following three methods can generally be conceived:
(1) A first method is one according to which all music editing operations are completed by using another medium such as a magnetic tape, TOC information is prepared from the result of the editing operation and recorded in the disc, and the edited music information is continuously dubbed from the tape to the disc. PA1 (2) A second method is one according to which recording is made continuously on a disc in real time and, thereafter, TOC information is prepared from the result of recording and recorded in a TOC area of the disc. According to this method, it is necessary to input music head information by operation of a music head indicating key by a user during recording or to detect the music head information automatically during recording and input it. PA1 (3) A third method is one according to which, as a modification of the second method, TOC information is successively produced during recording of music information on a disc and this TOC information is stored in a non-volatile solid memory and, after completion of recording of all music pieces, the TOC information is read from the memory and written in the disc.
The above described first method cannot enable recording to be made in real time and, moreover, requires a recording medium other than the disc. Hence, the advantage of a disc recording and reproducing device of an MD type disc is not gained from this method and therefore this method is not suitable for a home use.
In the second method, when supply of an electric power is stopped due to stoppage of electricity or accidental pulling off of a power plug by the user or some other cause during recording, the recording is stopped without writing the TOC information and, accordingly, not only a music piece-recording of which has been interrupted but all other music pieces which have so far been recorded cannot be reproduced so that recording must be made from the beginning again. Even if the music pieces can be reproduced, the TOC information is still lacking and, hence, a high speed search utilizing the TOC information will have to be abandoned or the TOC editing will have to be made again.
The third method can solve the problem of the second method but it requires a very expensive non-volatile memory for this purpose with resulting increase in the manufacturing cost.
It is, therefore, an object of the invention to provide a disc recording and reproducing device which, in a case where plural music pieces are continuously recorded in real time on a disc, is capable of minimizing the trouble occurring in writing of data in the TOC area due to stoppage of supply of an electric power.